Antennas may be used for a variety of purposes, such as communications or navigation, and wireless devices may include broadcast receivers, pagers, or radio location devices (“ID tags”). The cellular telephone is an example of a wireless communications device, which is nearly ubiquitous. A relatively small size, increased efficiency, and a relatively broad radiation pattern are generally desired characteristics of an antenna for a portable radio or wireless device.
Additionally, as the functionality of a wireless device continues to increase, so too does the demand for a smaller wireless device which is easier and more convenient for a user to carry, yet uses relatively less power and/or has a longer standby time. One challenge this poses for wireless device manufacturers is designing antennas that provide desired operating characteristics within the relatively limited amount of space available for antennas, and that cooperate with related circuitry to use a reduced amount of power. For example, it may be desirable for an antenna to communicate at a given frequency with desired characteristics, such as bandwidth, polarization, gain pattern, and radiation pattern, for example, and for the wireless device to be operational for several days on a single battery or charge cycle.
It may be desirable that a personal communications device, for example, a cellular telephone, be relatively small in size. In other words, it may be desirable that the device volume and surface area are relatively limited. This, in turn, may result in size and performance trades between components, for example, having a relatively large battery may mean having a relatively small antenna. Compound designs may be desired to improve component integration.
The electrical power requirements of an electronic device, for example, have generally been reduced. For example, the field effect semiconductor has allowed even solar powered electronics to become increasingly popular. The solar cell may require increased product surface area however, which may be required for other purposes, for example, a keyboard.
Many antennas may include a combination of relatively good conductors and relatively good insulators for efficiency, for example. This may be particularly so in a microstrip patch antenna, for example, as strong near field reactive energies circulate in the printed wire board dielectric, which may cause heating losses. A solar cell which includes semiconductors, for example, are neither relatively good conductors nor relatively good insulators.
To achieve desired antenna characteristics, the size and shape of an antenna, for example, a patch antenna may be adjusted. For example, U.S. Patent Application Publication No. 2010/0103049 to Tabakovic discloses a patch antenna having a patch antenna element and a conductive layer and dual separated feeds coupled thereto. Each of the dual feeds has a conductor segment and a deltoid shaped conductive strip orthogonal to the conductor segment. U.S. Patent Application Publication No. 2009/0051598 to McCarrick et al. discloses a patch antenna having a solid geometry, for example, square, polygon, ellipse, oval, semicircle, and deltoid.
To reduce power consumption, the functionality of a photovoltaic cell may be combined with an antenna. For example, U.S. Pat. No. 6,590,150 to Kiefer attempts to combine the functionality of a photovoltaic cell and an antenna in a single unit. More particularly, Kiefer discloses a grid or front electrical contact, an anti-reflective coating, two semiconductor layers, a dielectric layer, and a ground plane layer configured in a stacked arrangement.
In an attempt to further provide space savings, several approaches disclose using a display and an antenna in a stacked relation. For example, U.S. Pat. No. 6,697,020 to Xing discloses an integrated multi-layer structure for a portable communications device that includes an antenna coupled between an LCD display and dielectric substrate. U.S. Pat. No. 6,774,847 to Epstein et al. discloses a chip antenna, a rigid printed circuit, a conductive material, a lens material, and a display coupled in a stacked arrangement.